|Conference|Date|Place|attendance|Archive of presentations|
|---|---|---|---|---|
|Wikimania 2005|August 5–7|Frankfurt, Germany|380|slides, video|
|Wikimania 2006|August 4–6|Cambridge, United States|400|slides and papers, video|
|Wikimania 2007|August 3–5|Taipei, ROC (Taiwan)|440|Commons gallery|
|Wikimania 2008|July 17–19|Alexandria, Egypt|650|abstracts, slides,video|
|Wikimania 2009|August 26–28|Buenos Aires, Argentina|559|slides, video|
|Wikimania 2010|July 9–11|Gdańsk, Poland|about 500|slides|
|Wikimania 2011|August 4–7|Haifa, Israel|720|presentations, video|
|Wikimania 2012|July 12–15|Washington, D.C., United States|1,400|presentations, videos|
|Wikimania 2013|August 7–11|Hong Kong|700|presentations, videos|
|Wikimania 2014|August 6–10|London, United Kingdom|N/A||

Question: how many wikimanias have been held in the usa?
Answer: 2